Brake cylinder



April 18, 1961 s. A. LINDSTROM BRAKE CYLINDER Filed April 25, 1958 INVENTOR. Wye (Z. oza'z rm United States Pa ent-O BRAKE CYLINDER Filed Apr. 25, 1958, Ser. No. 730,883

7 Claims. (Cl. 60-54.6)

My invention relates to power cylinder devices and more particularly to a duplex power cylinder device adapted to be used in conjunction with a brake arrangement.

An object of my invention is to provide a novel duplex brake cylinder arrangement which is less expensive to produce and easier to assemble than most conventional brake cylinders on the market today.

Another object of my invention is to provide a novel brake cylinder arrangement wherein misalignment of the piston with respect to the longitudinal axis of the related cylinder is prevented.

A still further object of my invention is to provide a novel brake cylinder arrangement wherein the outboard ends of the pistons are supported by end caps secured to the cylinder so that misalignment of the pistons with respect to the long axis of the cylinder is prevented durv 7 ing movement of the pistons along said axis.

A still further object of my invention is to provide a novel brake cylinder arrangement wherein contact between the pistons and the related cylinder wall is prevented thereby eliminating wear between the pistons and cylinder wall.

Another object of my invention is to provide a novel brake cylinder arrangement which utilizes a piston'ring and bushing, which are the sole support means for the related piston and rod, respectively, both of the former 'being readily and easily replaced in the event of wear thereto. i 1

A still further object of my invention is to provide a novel brake cylinder arrangement utilizinga flexible boot interconnecting the related end cap and piston rod and which has a cross-slit to allow the'passage of air through an opening in the end cap, from and into the chamber enclosed between the end cap and related piston during movement of the piston towards 'and away from, respectively, the endcap.

These and other oblects W111 become apparentl from the following description and drawings, wherein; V

Figure 1 is an end elevational view of a brake cylinder arrangement embodying the invention;

Figure 2 is a sectional view taken along mega- 0t Figure 1;

Figure 3 is a detail side elevational view of the retaining ring utilized in the embodiment of Figure 1;

Figure 4 is an edge elevational view of Figure 3, as seen from the right;

Figure 5 is a fragmentary detail side elevational view of the piston packing utilized in the embodiment of Figure 1;

Figure 6 is an edge elevational view of Figure 5, as seen from the right;

Figure 7 is a sectional view taken along the line 77 of Figure 5; and

Figure 8 is an enlarged sectional view of a portion of the bellows structure illustrated in Figure 2 of the drawing.

To achieve clarity, certain structural details have been be integral therewith.

. Patented Apr. 18, 1961 omitted from certain views where said details are more clearly shown in other views.

Referring'now to the drawings. for a better understanding of theinvention, there is shown a duplex brake cylinder generally designated 10, comprising legs 12 which are preferably integral therewith and which carry the cylinder when the latter is releasably secured to a frame or support (not shown) adjacent a related brake arrangement (not shown) in order to actuate the brake. Disposed within the cylinder 10 and located approximately centrally'thereof, may be an annular groove 14 in the inner perimeter of a cylinder wall 16. A split retaining ring 18 (Figures 1-4) may be-received in said groove 14. The retaining ring 18 may be interrupted or broken to form the ends 20 which may be separated or spaced from each other when the ring 18 is in an inoperative position. As will be seen most clearly in Figure 3, the retaining ring 18 progressively increases in width with the width of the ring being narrowest adjacent the ends 20; Each end 20 may have an aperture 22 for reception of an associated tool (not shown) whereby the ends 20 may be brought together during assembly or disassembly of the ring 18 from the grooves.

As will be known to those familar in the art, and asshown in phantom lines in Figure 3, the structural arrangement of the retaining ring 18 permits the tool (not shown) to bring the ends 20 together in order to assemble ring 18 in groove 14. The ring 18, because of its resiliency, will have a tendency to space the ends 20 apart trom each other as the tool (not shown) is released and removed from the apertures 22.

In Figure 1, the retaining ring 18 is shown in dotted lines with'the groove 14 being of sufficient depth to per-' mit the ends 20 to be spaced fromeach other subsequent to assembly of ring 18 in the groove 14. Disposed between the ends 20 and intersecting the groove 14 may be a pair of openings 24 which extend from the groove 14 to the exterior of the housing 10 to afiord reception of a pair of roll pins 26 which extend into the groove 14 and which may be engaged by the ends 20 of the ring 18 to limit rotational movement of the ring 18 in the groove 14. Disposed between and substantially parallel to the openings 24 may be an inlet 28 to afford escape of pressure fluid subsequent to actuation of the associated brake arrangement (not shown). The rollpins 26 thus prevent the ring 18 from closing the inlet 28.

Disposed within the housing 10 may be a pair of opposed pistons 30, each comprising a rod 32 which may As will be readily seen in Figure 2, each piston 30 may be spaced from the cylinder wall 16 by a very smooth hard piston ring 34 which may be disposed within a groove 36 of the related piston 30.

The ring 34 is formed, for example, of canvas impregnated with phenolic resin and is press-fitted on the piston. If the ring becomes loose in service, it may be retained by 'a resilient packing 38 (Figures 2 and 5 through 7) which' may have its inner and outer perimeters tapered and which may have a tapered groove 40 disposed subto afiord insertion of the latter in groove 42 with the groove 40 of the packing 38 facing toward the open end of groove 42. The open end of the groove 42 is partly obstructed by an annular retainer rib 42a to prevent accidental loss of the packing 38. The inner and outer perimeters of the packing 38 are normally tapered but when inserted in the groove 42 the inner and outer perimeters may be forced inwardly towards the groove 40 to the working position shown in Figure 2, and thus may reduce the taper of the groove 40. The tendency of the packing material is to return to its original shape and thus the material of the packing 38 forces the inner perimeter into the groove 42 and the outer perimeter against the cylinder wall 16 and will continue to exert such force even as the material wears and the outer perimeter decreases. It may be readily seen, therefore, that the ring 34 and packing 38 coact to prevent the passage of fluid between the piston. 30 and cylinder Wall 16. i 1 1 The piston 30 may be guided or supported by an end cap 44 located adjacent the related open end of the housing 10. The outer periphery of the end cap 44 may be disposed within a groove 46 of the cylinder and the cap 44 may have an aperture 48 which comprises a bushing slot 51) for reception ofan annular. bushing 52. The bushing 52 is preferably formed of .a very hard smooth material such as that of which ring 34 is formed. The bushing 52 may engage the piston rod 32 and space the latter from the end cap 44 to thereby reduce wear on the surfaces of the cap and piston rod. Each end cap 44 may be retained by a resilient retaining ring 54 substantially similar in construction to ring 18. A

Because the packing 38 is flexible, the ring 34 and bushing 52 alford the sole guide means to maintain con.- centricity between the longitudinal axes of the cylinder and the piston rod assembly. Inasmuch as the ring 34 and bushing 52 are less resistant to wear in service than the cylinder and piston, the device may be quickly reconditioned by replacing ring 34 and bushing 52.

A boot or bellows 56 formed of flexible material, preferably rubber, may be secured to the free end of the rod 32 and to the outer surface of the end cap 44 to thereby protect the piston from snow and ice during the time the cylinder may be applied'during application of a related brake (not shown) or while the brake is released. 1

Each end cap 44 may have an opening 58 and each related boot 56 may have -a cross-slit 59 so that the fluid located between the end cap 44 and piston 30 may escape to the atmosphere during'actuationof the power cylinder.

It should be noted that even though, the invention discloses a duplex power cylinder arrangement comprising a cylinder utilizing two pistons and two rods, the arrangement may be modified wherein the cylinder may utilize only one piston and one rod to accomplish the desired result of actuation of a related brake arrangement.

It should be additionally noted that the cylinders 30 may be returned to their released position shown in Figure 2, by spring-release means (not shown) located on the brake arrangement (not shown).

It is to be understood that I do not wish to be limited by the exact embodiment as shown, which is merely by way of illustration, and not limitation, as various and other forms of the device will, of course, be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the appended clair \s.

I claim:

1. In a fluid actuated duplex power cylinder device, the combination of: a cylinder open at opposite ends;

a pair of opposed pistons disposed for reciprocating movement within the cylinder and having piston rods extending outwardly in opposite directions from each other; a removable stop member releasably disposed entirely within the cylinder between the pistons for limiting movement of the pistons toward each other; a pair of removable end closure members releasably disposed within the cylinder at opposite ends thereof for closing their related ends of the cylinder and for receiving and guiding the rods of their related pistons through their entire stroke to maintain them in axial alignment with each other at all times; and means for introducing pressure fluid into said cylinder between said pistons.

2. A duplex power cylinder device according to claim 1, wherein the removable stop member comprises a resilient annular retainer ring releasably disposed within a groove on the inside of said cylinder.

3. A duplex power cylinder device according to claim 2, wherein said retainer ring is interrupted and has ends which are spaced from each other when the ring is in operative position and which are spaced further from each other when the ring is not in operative position.

4. A duplex power cylinder device according to claim 3, wherein the ends of the ring are provided with holes to accommodate receipt of a tool used for insertion or removal of the ring from the groove of the cylinder.

5. A duplex power cylinder device according to claim 1, wherein each of said end closure members comprises an end cap with an aperture for receiving the rod of a related piston, an abutment on the cylinder engageable with an inner surface of the cap, and a split ring releasably disposed within another groove of the cylinder wall for abutting engagement with an outer surface of said cap and operable to retain the end cap in position.

6. A duplex power cylinder device according to claim 5, wherein said end closure member also includes a flexible bellows interconnecting the end cap and the outer end of the rod of the related piston.

7. A duplex power cylinder device according to claim 6, wherein said end cap has a passageway extending :therethrough afiording communication between the interior of the cylinder and the interior of the bellows, and wherein the bellows has a passageway extending therethrough afiording communication between the interior of the bellows and the atmosphere to permit the flow of air between the atmosphere and the interior of the cylinder as the piston moves toward and away from the related end cap.

References Cited in the file of this patent UNITED STATES PATENTS 1,647,975 Tuttle et al. Nov. 1, 1927 1,758,671 Loughead et al. May 13, 1930 2,294,351 White Aug. 25, 1942 2,356,909 Aske Aug. 29, 1944 2,596,298 Shrefiler May 13, 1952 2,608,452 Hollingsworth Aug. 26, 1952 2,750,746 Brannen June 19, 1956 2,785,534 Tucker Mar. 19, 1957 

